Pneumatic separator



H. M. PLAIS-T ED.

- PNEUMATIC SEPARATOR. APPLICATION FILED FEB. H, 1919.

Patented July 29, 1919.

2 SHEETS-SHEET I.

H. MJPLAISTEDf PNEUMATIC SEPARATOR.

APPLICATION FILED FEB. 17 I913.

Pafentul July 29,1919.

2 SHEETS-SHEET 2.

m m m I valve in the form of a hinged door acting as ED STATES. PTE ePNEUMATIC SEPARATOR.

Specification of Letters Patent.

Application filed February 17, 1919. Serial No. 277,623.

To all whom it may concern Be it known that I, HAROLD M. PLAIs'rEn, acitizen of the United States, residing at St. Louis, Missouri, haveinvented certain new and useful Improvements in Pneumatic Separators, ofwhich the following is a specification.

This invention relates to certain new and useful improvements inpneumatic separators the peculiarities of which will be hereinafterdescribed and claimed.

The mainobject of my invention is the provision of-means for producing acen' densed side of said stream and collecting the Another object is thegraded particles. regulation of the linear velocity and quantity of air,according to the weight and size of the said particles,'and therebydetermining the velocity and quantity of air required to conveyparticles of different 'material respectively.

In the accompanying drawing on which like reference letters indicatecorresponding parts, Figure 1 represents a plan view, partly in section,of a device exemplifying my improvements; Fig. 2 a vertical section -ofthe same on the line 22 of Fig. 1; Fig.

3 a detailed plan section of a tailings valve with skimming wing; Fig. 4another detail view of a tailings valve of modified form; Fig. 5 asimilar detail view of a tailings a skimmer; Fig. 6 a .verticalsectional View of the valve shown in Fig. 3 'wlth adyacent parts; andFig. 7 an elevation of a grinding" and separating system with myimproved pneumatic separator applied thereto.

In other forms of pneumatic separators the particle-laden air is drawnby suction, or driven by blast, into a chamber of larger diameter thanthe pipe leading thereto,

whereby the velocity of the air is suddenly decreased by-the expansiondue to entering the chamber, and the material particles a suddenloosening of its hold upon the particles carried by the air, and the airis then picked up again. by the suction, or is again forced .onward whena blast system is used, in order to carry't'he finer particles out totheir final collection or separation.

In my system however a continuous current of air is produced either bysuction or by blast, in a conduit of practically uniform cross sectionalarea, which conduit is formed, in the preferred construction, in a flathorizontal spiral about a vertical axis. One end of the conduit, such asthe outer end of the spiral, serves as the inlet for the air, and theother end of the spiral serves as. the outlet for the air and finestparticles that have not been deposited in compartments connected toregulated openings in the side walls of the conduit, or in the bottom ofthe conduit, at definite periods Fatented July 29, 1919.

throughout its length. By the spiral form of with increasing angularvelocity as the stream approaches the center or outlet of the spiral. Bythis centrifugal action on the particles carried by the stream of air,the particles are condensed along the outer side Wall of the conduitcontinuously, and tend to pass outward through openings in said wallinto compartments connected therewith. As the velocity of the airnecessary to carry comminuted material of the kind generally ground andpulverized is much greater than that due to gravity, the particles willtend to hug the outer side wall of the conduit in greater condensationthan along thev bottom of the conduit. I have therefore provided thelarger number of openings for the escape of tailings in the side wallsof the conduit; and sir the particlesare of different size I haveprovided means for varying the size of the tailings openings for morereadily controlling the grade and uniformity of the tailing}? passingthrough said openings.

hile my improved separator may also with air under pressure, I prefer touse it with an exhaust system or with air under by the shaft of a mill Bhaving a driving 'the said fan A andleads to the outlet J of a spiralseparator of improved form comprising horizontal top wall K and bottomwall L forming parallel planes, between which is formed aicontinuousspiral conduit by means 15 of a vertical wall, preferably double, and

curved horizontally about a vertical axis,

and extending from the outer. end of the A practical form ofconstruction is to make the top and bottom walls of the separator ofwood, matched and joined, and stiffened by angle iron, as indicated inFigs. 1 and 2. One Wall, preferably the bottom, is

ooved at 9 to receive the vertical walls beore mentioned, and when suchwalls forming the sides of the conduit are doubled as shown in thepreferred form in Fig. l, the

' intermediate space between the continuous 40 wall R and the 'tailingswall S, isprovided with filler blocks T that also serve as stops orpartitions across said intermediate space,

. between the tailings openings in said wall S. The connecting bpltsthrough top and bottom v walls passbetween said walls R and S and thuspresent no obstruction to the streamof fair in the conduit passage. Thebottom wall is preferably grooved, as shown in Fig.

2, for both of said vertical walls R and S,

and alayer of felt is is interposed between the lower side of the topwall and the up er edges of the said walls R and S, to e ect practicallyair. tight contact between the same.

I designate the tailings openings in said wall .8 by the letter U,and'in each opening is mounted a valve or regulating device to vary thesize of said'opening,-such as a vertical pipe V passing downward throughthe bottom wall into a compartment 10 provided with a slide, but airtightin normal condition and adapted to receive the tailings passingthrough said pipe V, or other inlet thereto. The upper part of the saidpipe is 66 preferably provided with a closing dlsk W,

and central pin X passing through the upper wall and having a crank armY secured thereto for turning said pipe. A pin 3 or other means acts asa stop for the arm Y, and a packing washer I prevents the en-' 70 tranceof air around the central pin X. Be-

low the disk W is an opening 5.in the pipe extending to thebottom wall,which opening is preferably provided with a wing 6v that extendsoutthroughthe opening U into i the conduit space, amore or less distanceaccordmgt'o the rotation of the pipe V. When the wing is rotated to makecontact with the wall Sby its outer edge, the opening U is closed. Thenormal-position however is with go the wing extending into the conduitpassage as shown in Fig. 1, and varied accordmg to the material beingseparated. By practical use I have found that the openings U should beless in size near the beginning 35 of the spiral, and that the openingmay be increased in size by adjusting the valves or otherwise asweapproach the center of the sp ral. In some material containingrelatively heavy particles I prefer to use the form of the valve shownin Fig. 4 in which the wing 6 is directed inward,-that is, in

the intermediate space between the walls R and S,-instead of outwardinto the conduit as in Fig. 3. The bottom wall hasan open-v ing Ycorresponding to the pipe V and communicating .with the closed compart-1 ment 10 below the separator. The wing 6 Fig. 4, closes the opening Uby swinging like a door uponthepivot pin X, which may extend throughtheupper wall and have a lever arm or crank to turn it in the same way asthe center pivot pin of Fig. 6. 1

Fig. 5 shows th's form 6' with the hinge at thefarther side of the wingand with the wing itself projecting intothe passage to act as a skimmerin'the same way as the wing 6 of the pipe V.

While all the particles in the moving stream of air are subject tocentrifugal action, the heaviest particles or those of heavy material,will be' more influenced by gravity than particles of a light materialand smaller size. For this heavy material or heavy particles, I providetailings openings V in the bottom Wall and adjacent to the inner wall S,and provided with any suitable form of adjustable valve, preferably theone shown in Fig. 5 with the wing {3 extending upward when open, andclosmg the opening in the bottom when depressed by a handle Y Fig. 6.

In the pipeI connecting the fan with the outlet to the separator, Iprovide an air inlet valve 8, by opening which the suction through theseparator is reduced acc0rd-, ingly. In .handling fine and lightmaterial.

the velocity of the air and quantity of the air passing through theseparator, may thus be varied to correspond with the material beinghandled. In a full size construction of this separator I have found thatpulverized bituminous coal wei hing 39 lbs. per cubic foot and 67%passmg 150 mesh can v be handled with an air velocity of 3800 feet perminute. On the other hand barytes weighing 136 lbs. per cubic foot of agrade of 60% passing 350 mesh requires the full 'power of the exhaustfan, which in this case gave 4500 feet per minute in velocity of the airpassing through the separator. It was also found that a finelypulverized earth weighing 27 lbs. per cubic foot and of over 99%350mesh, would be car ried through with a larger opening of the air valve 8and a corresponding decrease of velocity and quantity of air required tohandle it through the separator. By this separator and air regulatingvalve, Iam able to determine the velocity and quantity of air requiredto move any material in par- I ticles in a stream of air as a vehicle,as well as to separate any desired grade of said particles from the a1rin said stream.

1. A pneumatic separator comprising horizontal top and bottom wallshaving outlets, an interposed partition forming a continuous spiralpassage of unobstructed cross sectional area for particle-laden aircurr'ent,said partition consisting of an imperforate outer wall and aninner Wall having tailings outlets, and valves mounted between saidpartition walls and forming regulatable passages from said tailingsoutlets in said partition to said-outlets in said bottom wall,substantially as described.

2. A pneumatic separator comprising a top combination with walls forminwall, a bottom wall having tailings outlet openings, an interposedpartition con- 40 stituting a continuous passage under air suction fromits inlet to its outlet for carrying particle-laden air,said partitionconsisting of an outer imperforate wall, and an inner wall havingtailings outlet openings and forming a dead air space between them,

and air tight compartments located below said bottom and communicatingwith said tailings outlets under air suction, substantially asdescribed.

3. A pneumatic separator comprising a top, bottom and interposedpartitlon walls forming a continuous passage for particleladen aircurrents,said bottom wall and partition having adjacent tailingsoutlets,- rotatable pipes mounted in said tailings outlets and eachhaving a slot above said bottom wall provided with a lateral wingprojecting into said passage and more or less.

closing the outlet in the partition wall, sub- HAROLD M. IPLAISTED.

